General Meeting Summary 2/25/21

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PARTICIPANTS: A. Brown, A. Camsonne, A. Asarturyan, B. Wojtsekhowski, C. Munoz-Camacho, C. Yero, C. Hyde, R. Ent, H. Mkrtchyan, J. Roche, P. Medeiros, J. Roche, S. Lassiter, V. Tadevosyan, V. Berdnikov, T. Horn, F. Barbosa, D. Hamilton


CRYSTAL IRRADIATION (Carlos)

  • 10 Crytur crystals - fabricated in 2020
  • Transmittance before irradiation all above specs
  • Nominal irradiation 30 Gy at 1 Gy/min, at most 10% transmittance loss --> all very good and radiation resistant
  • radiation mostly uniform, source ~10cm away
  • High radiation dose run to 1 MRad (10 kGy) at 750 rad/hr (~13 hours of irradiation)
  • before did annealing
  • damage saturates at ~30% loss max.
  • after large crystals no recovery with blue light bleaching or natural recovery, BUT can be recovered by thermal annealing (Orsay: 250 degC)
  • Conclusion: crystal are radiation hard, within specs
  • Actions:
  • measure light yield
  • thermal annealing for a few crystals and check transmittance


DSG UPDATES (Aaron)

  • Radiall-to-SAMTEC HV cables
  • Fabrication
  • HV schematic
  • Testing
  • Note: connectors come as either 16 channels (32 pins) or 8 channels (16 pins)
  • cable configuration: 15+15+6
  • Hardware interlock system development
  • CSS BOY


MECHANICAL DESIGN/ENGINEERING UPDATES (Paulo/Steven)

  • Facilities signed off on platform design drawings
  • NPS Installation timelines plan developed
  • Action: obtain further feedback, discuss in more detail at next meeting


ANODE CURRENT MEASUREMENTS (Vladimir, Carlos Y., Josh, Fernando)

  • Anode current problem review
  • 13mA anode current - max dose 400 rad/h
  • 80mA anode current - dose at high Q2 (50uA) 2500 rad/h
  • Values factor 10 higher than should be - looks like need to cut gain by factor of 100 (assuming 10^5 gain, factor 1000 for 10^6 gain)
  • Next steps:
  • Response of setup Hamamatsu base (reference, 10^5 gain), then follow up with NPS
  • Then adjust HV to see range of gains that one can expect - then based on that study shorten dynodes
  • Note: FCAL measured nonlinearity at low amplitudes (~5%)
  • since have to cut gain may need to replace the NPS divider with one that gives a better linearity (different pre-amp and external low voltage power supply)


REFLECTOR SHAPING (Vladimir, Carlos Y., Josh)

  • Oven not yet accessible - two options are being investigated


NEXT MEETING: THURSDAY 4 MARCH 2021 AT 9:00AM ET

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